贫混凝土疲劳方程的建立及其应用研究

贫混凝土用于水泥混凝土路面或沥青混凝土路面基层时,和面层一起受到荷载应力和温度应力的反复作用,路面应力分析和结构设计时应考虑其疲劳性能.在室内贫混凝土小梁弯拉疲劳试验的基础上,分析疲劳寿命试验数据的概率分布,得出其疲劳寿命服从双参数威布尔分布,据此建立了不同应力水平和等效应力水平下两种形式的疲劳方程.根据此疲劳方程,得出贫混凝土的疲劳性能优于其他常用半刚性基层材料,并建立了贫混凝土作为水泥混凝土路面下面层荷载应力计算的疲劳应力系数,以及作为沥青路面基层层底弯拉应力验算的弯拉强度结构系数.

Study on formulation and application of fatigue equation for lean concrete

When set as the base of cement concrete pavement or bituminous pavement,lean concrete withstands the repeated actions of load stress and temperature stress together with the surface,and therefore,the fatigue character should be considered in the pavement stress analysis and structure design.Based on the indoor flexural tensile fatigue tests of the small beam and through analyzing the probability distribution of fatigue life,authors of this thesis concluded that the fatigue life of lean concrete agrees to the two-parameter WEIBULL distribution.Two types of fatigue equation under different stress level and equivalent stress level were built up.With the fatigue equations,the authors discovered that the fatigue property of lean concrete is better than common semi-rigid base materials,and eventually formulated the load fatigue stress coefficient used in load stress calculation for lean concrete as undersurface of cement concrete pavement,and the tensile strength structure coefficient used in the tensile stress check for lean concrete as base of asphalt pavement.